Referring to FIG. 5, a prior art traction-type elevator has a car 3 that moves vertically by a pair of car guide rails 2a and 2b, and a counterweight 10 that moves vertically along a pair of counterweight guide rails 1a and 1b. A rope 6a connecting the car 3 and the counterweight 10 is driven by a hoisting machine 5. When the hoisting machine 5 is installed in an upper part of an elevator shaft 15, the hoisting machine 5 is supported on the pair of counterweight guide rails 1a and 1b in a space between the car 3 and a side wall of the elevator shaft 15. (Jpn. Pat. App. Hei 7-308515).
In this prior art elevator, the center of gravity of the car 3 that moves vertically along the pair of car guide rails 2a and 2b is apart from the center of the pair of counterweight guide rails 1a and 1b and hence a high force acts on the hoisting machine 5. Therefore, a high bending force act on the pair of counterweight guide rails 1a and 1b. 